A disadvantage of this design is that the user's seating comfort may be adversely affected by the rigid housing of the airbag module, because the contour of the housing pushes through the foamed upholstery. Additionally, the re-upholstery of such seats of an automobile becomes more difficult as airbag modules are normally provided on one side only of the seat of an automobile, and asymmetric reference tension results from the housing provided in the foamed upholstery.